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A. P. BRUSH.

CARBURETEH.-

APPLICATION mm JUNE 21.

Patented May 20, 1919.

n erases as nron.

sunset? 2?. BRUSH, or DETROIT, MICHIGAN.

.CARBURETER.

Specification of Letters Patent. Patented May 20, 1919i.

Application filed June 27, 1917. Serial No. 177,193.

To all whom it may concern:

Be it known that I, Amxson P. Bnnsn, a

' citizen of the United States, residing atDetroit, in the county' of llayne and State of Micln an have invented a certain new and useful Improvement in Carburetors, of

'\VliiCh the following is a full, clear, and

out definitely in the appended claims.

present invention is embodied. Fig. 2 is a Inthe' drawings, Figure 1 is a sectional side elevation of the carburetor in which the front elevation thereof, on a smaller scale.

Referring to the parts by reference characters, 10 represents the air tube of the carbureter; andthis is preferably flanged at its discharge end to facilitate its connection with the inlet manifold of the-engine. The

other end of the air tube. during the ordinary running conditions, is open to the at mosphere. The valve 12in this tube, adjacent the air inlet end thereof. is merely a choke valve which may be closed to whatever extent is necessary to promote the starting of the engine. I

In this air tube is a balanccdsuction controlled valve 15 which, when closed will substantially, prevent any flow of air through the air tube. This valve as shown'is a light piston having a nieeslidihg tit in a cylinder 16. which is closed at its upper end by a tightly fitting cap plate 1 said cylinder 'he ing preferably cast integral with the air tube with its axis at right angles thereto. The piston valve is of such length that when it is down, and therefore shutting ot? the flowof air through the air tube. it will still projeet'into this cylinder. A light spring 17 arts to hold the valve in the closed position, but with a force such that a slight reduction of the air pressure in the cylinder 16 will cause said valve to lift. The tension of the spring may be adjusted by means of a screw 18 which screws down through the plate 14, and has on its lower end a pressure plate 19 that bears uponthe top of said spring 17.

20 represents the carburetor float chamber and 21 the fuel discharge nozzle therefrom. Thls nozzle discharges upward through a calibrated jet opcning into a fuel vaporizing tube 25. This tube 25 1S extended to and is in open communication with the air tube 10 adjacent the discharge end thereof. For a. part ot its length this tube is so dlsposed that it will be sutlieiently heated by the exhaust gases to cause the result hereinafter specified. As shown this tube passes vertically through the exhaust manifold 30 of the engine. The walls of the tube are of thin metal; and therefore will be heated by the exhaust gases. lVithin this tube 25 at some suitable point between the nozzle 21 andthe exhaust manifold is a restricted calibrated opening 26. In this tube 25 is also a hole 27' to the. atmosphere. A valve 28 is, however,

provided for closing this hole or. opening it to any degree required. This valve screws down through a boss on the upper wall of the tube 95, and is provided with an operating handle whereby it maybe turned to whatever extent is desired. This valve serves 'as the air throttle valve. for the deyice.

An air tube 32 extends from the vaporizing tube 25 to the upper end of the cylinder.

16 and is in open eonununication with both. hen the engine is idle'the valve 15 will be closed by its spring and by the action of gravity. turned over forthe purpose of starting 1t,.

lVhen, however, the engine, is-

the valve 28 should be nearly closed. Therefore, on the suction strokes of the engine, there will beproduccd in the tube 25 such a reduction of pressure as will cause fuel to, flow from nozzle 21 and thence through the calibrated opening .26. and to be thor ughl 9 5 atomized and drawn into the air tube 10. At this time the valve 12 should be nearly closed so that even if the valve 15 should open a very small quantity only of air will be. admitted to the device through the aha-1m tube 10 for mixture with the fuel. The re-f sult will he that. at first. a very rich mixture of fuel vapor or spray and air will be diseharged into the air tube 10 nd will thence flow into the engine.

to keep the. engine idling. i. (a. merelvruuning without carrying load, the an throttle valve 28 should he opened.

When the valves are. in the stated posi- 1 0 tions, the volume of the explosive mixture. formed Wiil be small, and will be made up \Vheu the engine is started, the valve 12 should be opened: and

for most part of such air as enters through the small valve controlled opening 27; and the spray and vapor of fuel drawn through the nozzle. After the engine has been running for a short time the part of tube 25 which is within the influence of the exhaust gases will get very hot; wherefore all of the mixture of air and fuel which flows through tube 25 will get highly heated ;a condition which is particularly desirable when the engine is idling, or running under a very light load.

When it is desired to produce a larger volume of less rich mixture, the air throttle valve 28 is turned toward the closedposition. At each suction stroke of he engine, a reduction of pressure will be produced in tube 25, and this will increase the rate of fuel flow through the fuel nozzle. But as the pressure is reduced in the tube 25, so will it be reduced in cylinder 16; and this will cause a. proportionate opening of the valve 15 thereby permitting air to flow through tube 10 to mix with the very rich mixture flowing through the tube 25.

If valve 26 be entirely closed there will be practically nothing but fuel spray and vapor which flows through the tube 25; but in that event the valve 15 will be opened widely enough to supply the necessary air to produce when mixed with said fuel, a mixture of the required proportions, and in sufiieient volume to cause the engine to de liver the maximum power output.

It is easy to determine what size the calibrated opening 26 should be in order that, when valve 28 is closed, a given reduction of pressure in tube 25 adjacent the nozzle will be produced by each suction stroke of the engine to which the carburetor is to be at tached. It is likewise easy to determine the necessary size of the nozzle jet opening 21 in order that a certain reduction of pressure shall cause the desired rate of fuel flow into said tube 21.

Having made these openings 26 and 21 of the proper sizes, one may control the actual reduction of pressure in tube 25 and cylinder 16, due to the suction strokes of'the engine, by opening and closing the valve 28, so as, at all times, to proportionately increase or diminish the rate of flow of fuel .into and of air through the air tube 10. i

What actual ratio of fuel and air will be in the explosive mixture so formed will depend largely upon the responsiveness of valve 15 to changes of pressure in cylinder' 16. This obviouslyinay be regulated to produce the desired ratio by adjusting the tension of the spring 17 Y Not only does the described construction provide means to control the delivering to the engine an adequate volume of explosive mixture to produce desired variations in the power outputof the engine, but it produces other results which contribute largely to the efficiency of the engine. All of the fuel and air which passes through the hot part of,

throttle is positioned as stated to cause this result, only the fuel content of the produced mixture is heated, while the greater part,- the air of the mixture, is not heated The result is a relatively cold mixture, which causes high compression in the cylinder, which is desired under the conditions stated. It is also obvious that by the manipulation of the throttle the described changes are produced gradually.

Having described my invention, I claim: 1. In a carburetor, the combination of an air tube, an automatically-closing suction controlled valve to vary the rate of air flow therethrough, a small fuel tube whose diameter is substantially less than the diameter of the air tube, and which is in open communication with the air. tube between the discharge end thereof and the valve therein, a fuel jet nozzle in communication with a source of fuel supply and arranged to discharge into said fuel tube, means to prevent and regulate the admission of air into said fuel tube, and means to subject the air tube valve to substantially the same reduced pressure conditions as exist in said fuel tube adjacent the fuel jet nozzle.

2. In a carburetor, the combination of an air tube, an automatically-closing suction controlled valve to vary the rate of air flow therethrough, a small fuel tube which is in open communication with the air tube between the discharge end thereof and the valve therein, a fuel jet nozzle-in communication with a source of fuel supply and arranged to discharge said fuel tube, means to prevent and regulate the admission of air into said fuel tube, and means tosubject the air tube valve to substantially the same reduced pressure conditions as exist in said fuel tube adjacent the fuel jet nozzle, the exhaust manifold of the associated engine, the said fuel tube being extended through said exhaust mahifold.

3. In a carburetor, the combination of an air tube, asuction controlled valve to vary the rate of air flow therethroughfa small fuel tube which is in open communication with the air tube between the discharge end thereof and said valve, a fuel j etnozzle con-v eeaeee :3

nected with the source of fuel. supply and being in said fuel tube a valve-controlled air discharging into said fuel tube, said fuel opening for the admission of air into the tube being restricted to a small passageway same. 1 between the fuel jet nozzle and the discharge 5. In a carbureter, the combination of an 5 end of said fuel tube, means to control and air tube, a cylinder in open communication regulate the flow of air into said fuel tube, therewith, a piston valve movably supported and means to subject said air tube valve to in said cylinder and adapted to extend substantially the same reduced pressure conacross and close said air tube, a fuel tube ditions as exist in said fuel tube adjacent connected with said air tube between the 30 the fuel nozzle. discharge end thereofand said valve, a fuel 4. In a carbureter, the combination of an get nozzle in communication with a source of air tube, a cylinder in open communication fuel supply which discharges into said fuel therewith, an automatically closing piston tube, a pipe connecting said fuel tube with valve movably supported, in said cylinder said cylinder there being in said fuel tube .a 35' and adapted to extend across and close said valve-controlled air opening for controlling a air tube, a fuel tube connected with said air the admission of air into the same, a spring tube between the discharge end thereof and acting on said valve to close .it and means said valve, a fuel jet nozzle in communicato adjust the tension of said spring.

tion with a source of fuel supply which dis- In testimony whereof, I hereunto aflix my 41 charges into said fuel tube, a pipe connectsignature.

ing said fuel tube with said cylinder, there ALANSON P. BRUSH. 

